A technology to blend a polyamide/polyphenylene ether resin composition with a hydrogenated block copolymer prepared by hydrogenating a block copolymer comprising at least one polymer block mainly composed of an aromatic vinyl compound and at least one polymer block mainly composed of a conjugated diene compound includes, for example, those disclosed in Patent Documents 1 to 4 as described below.
The hydrogenated block copolymers suitably used in the polyamide/polyphenylene ether resin compositions are often in the form of a bulky amorphous powder which is called “crumb-shaped” among those skilled in the art. However, the block copolymers have a low bulk density, and it is often difficult to feed them in abundance into an extruder in terms of feeder capacity. Consequently, the feed rate of the hydrogenated block copolymers is restricted to within a certain limit, which in turn had to limit the productivity (production volume per unit time) of the polyamide/polyphenylene ether resin compositions.
In particular, remarkable improvement in the performance of a twin-screw extruder (the emergence of a megacompound type extruder) in recent times enables production at high-revolution and high-discharge rate, which in turn requires further increase in productivity per unit time of a resin composition. In spite of the requirement, the problem that productivity cannot be improved as expected gradually manifests itself due to the drawback of the hydrogenated block copolymer regarding the bulk density thereof as described above. In order to eliminate the problem, a technique is adopted in which the hydrogenated block copolymer is preblended with other resin components to reduce the overall bulk density for feeding the copolymer. However, the technique largely restricts the degree of freedom of the process. Thus, it is desired to significantly increase the productivity in terms of the technology for blending a polyamide/polyphenylene ether resin composition with a hydrogenated block copolymer.
Patent Document 1: Japanese Patent Laid-Open No. 62-151456
Patent Document 2: Japanese Patent Laid-Open No. 64-79258
Patent Document 3: International Publication WO 2002/94936
Patent Document 4: National Publication of International Patent Application No. 2004-518774